Carbazole compound and organic light-emitting device including the same

ABSTRACT

A carbazole compound represented by Formulae 1A or 1B: 
     
       
         
         
             
             
         
       
         
         
           
             wherein in Formulae 1A and 1B, A, R 1  to R 4 , and c1 to c3 are described in the specification.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Korean Patent Application No. 10-2014-0162851, filed on Nov. 20, 2014, in the Korean Intellectual Property Office, and Japanese Patent Application No. 2013-273385, filed on Dec. 27, 2013, in the Japanese Patent Office, and all the benefits accruing therefrom under 35 U.S.C. §119, the contents of which are incorporated herein in their entirety by reference.

BACKGROUND

1. Field

The present disclosure relates to a carbazole compound and an organic light-emitting device including the same.

2. Description of the Related Art

Organic light-emitting devices (OLEDs) are self-emission devices that have wide viewing angles, high contrast ratios, short response times, and excellent brightness, driving voltage, and response speed characteristics, and produce multicolored images.

A typical organic light-emitting device may include an anode, a cathode, and an organic layer that is disposed between the anode and the cathode and includes an emission layer. In an organic light-emitting device, a hole transport region may be formed between the anode and the emission layer, and an electron transport region may be formed between the emission layer and the cathode. Holes provided from the anode may move toward the emission layer through the hole transport region, and electrons provided from the cathode may move toward the emission layer through the electron transport region. The holes and electrons may be recombined in the emission layer to produce excitons. These excitons may change from an excited state to a ground state, thereby generating light.

In order to improve emission efficiency of the organic light-emitting device, the emission layer may include a host. As a host material, a carbazole compound having hole-transporting capability and a large energy band gap in a triplet state can be used. Particularly, a carbazole compound, such as 4,4′-N,N′-dicarbazole-biphenyl (CBP) or 1,3-bis(carbazole-9-yl)benzene (mCP), is known to be used as a host material of the organic light-emitting device.

JP 2003-335753 A discloses a carbazole compound having electron-transport capability provided by substituents introduced to the N-, 2-, and 3-positions of the carbazole moiety.

However, the carbazole compound including a functional group for electric charge transport introduced to the N-, 2-, and 3-positions of the carbazole moiety as disclosed in JP 2003-335753 A has problems with decreasing energy band gap values in a triplet state.

Thus, there remains a need in a carbazole host having electric charge transporting capability and a large energy band gap in a triplet state to ensure its optimal performance in an organic light-emitting device.

SUMMARY

Provided are a new carbazole compound having electric charge transporting capability and a large energy band gap in a triplet state to solve the problems, and an organic light-emitting device including the carbazole compound.

Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented exemplary embodiments.

According to an aspect of an exemplary embodiment, there is provided a carbazole compound represented by Formulae 1A or 1B below:

In Formulae 1A and 1B,

-   -   A is -(L₁)_(a1)-(E₁)_(b1),     -   L₁ is selected from a substituted or unsubstituted C₆-C₆₀         arylene group, and a substituted or unsubstituted C₁-C₆₀         heteroarylene group;     -   E₁ is a substituted or unsubstituted electron         transporting-cyclic group or a substituted or unsubstituted         carbazolyl group, each of which includes at least one N as a         ring-forming atom;     -   a1 is selected from integers of 1 to 3;     -   b1 is 1 or 2, provided that when b1 is 2, two groups E₁ are         identical to or different from each other;     -   R₁ is selected from a deuterium atom, —F, —Cl, —Br, —I, a         hydroxyl group, a cyano group, a nitro group, an amino group, an         amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid group or a salt thereof, a sulfonic acid group         or a salt thereof, a phosphoric acid group or a salt thereof, a         substituted or unsubstituted C₁-C₂₀ alkyl group, a substituted         or unsubstituted C₂-C₂₀ alkenyl group, a substituted or         unsubstituted C₂-C₂₀ alkynyl group, and a substituted or         unsubstituted C₁-C₂₀ alkoxy group;     -   R₂ to R₄ are each independently selected from a deuterium atom,         —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro         group, an amino group, an amidino group, a hydrazine group, a         hydrazone group, a carboxylic acid group or a salt thereof, a         sulfonic acid group or a salt thereof, a phosphoric acid group         or a salt thereof, a substituted or unsubstituted C₁-C₂₀ alkyl         group, a substituted or unsubstituted C₂-C₂₀ alkenyl group, a         substituted or unsubstituted C₂-C₂₀ alkynyl group, a substituted         or unsubstituted C₁-C₂₀ alkoxy group, a substituted or         unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or         unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or         unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or         unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or         unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted         C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀         arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl         group, a substituted or unsubstituted monovalent non-aromatic         condensed polycyclic group, the substituted or unsubstituted         monovalent non-aromatic condensed heteropolycyclic group,         —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), and —B(Q₁₆)(Q₁₇);     -   c1 to c3 are each independently 1 or 2;     -   at least one of substituents of the substituted C₆-C₆₀ arylene         group, the substituted C₁-C₆₀ heteroarylene group, the         substituted electron transporting-cyclic group, the substituted         carbazolyl group, the substituted C₁-C₂₀ alkyl group, the         substituted C₂-C₂₀ alkenyl group, the substituted C₂-C₂₀ alkynyl         group, the substituted C₃-C₁₀ cycloalkyl group, the substituted         C₁-C₁₀ heterocycloalkyl group, the substituted C₃-C₁₀         cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenyl         group, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀         aryloxy group, the substituted C₆-C₆₀ arylthio group, the         substituted C₁-C₆₀ heteroaryl group, the substituted monovalent         non-aromatic condensed polycyclic group, and the substituted         monovalent non-aromatic condensed heteropolycyclic group is         selected from     -   a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a         C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, and a C₁-C₂₀         alkoxy group;     -   a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl         group, and a C₁-C₂₀ alkoxy group, each substituted with at least         one of a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a         cyano group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl         group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl         group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a         C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀         heteroaryl group, a monovalent non-aromatic condensed polycyclic         group, a monovalent non-aromatic condensed heteropolycyclic         group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), and —B(Q₂₆)(Q₂₇);     -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic         condensed polycyclic group, and a monovalent non-aromatic         condensed heteropolycyclic group;     -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic         condensed polycyclic group, and a monovalent non-aromatic         condensed heteropolycyclic group, each substituted with at least         one of a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a         cyano group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a         C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, a C₁-C₂₀ alkoxy         group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl         group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl         group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀         arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent         non-aromatic condensed polycyclic group, a monovalent         non-aromatic condensed heteropolycyclic group, —N(Q₃₁)(Q₃₂),         —Si(Q₃₃)(Q₃₄)(Q₃₅), and —B(Q₃₆)(Q₃₇); and —N(Q₄₁)(Q₄₂),         —Si(Q₄₃)(Q₄₄)(Q₄₅), and —B(Q₄₆)(Q₄₇), and     -   Q₁₁ to Q₁₇, Q₂₁ to Q₂₇, Q₃₁ to Q₃₇, and Q₄₁ to Q₄₇ are each         independently selected from a hydrogen, a C₁-C₂₀ alkyl group, a         C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, a C₁-C₂₀ alkoxy         group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl         group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl         group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a         monovalent non-aromatic condensed polycyclic group, and a         monovalent non-aromatic condensed heteropolycyclic group.

According to an exemplary embodiment, there is provided an organic light-emitting device including:

-   -   a first electrode;     -   a second electrode facing the first electrode; and     -   an organic layer disposed between the first electrode and the         second electrode, wherein the organic layer includes an emission         layer and at least one carbazole compound represented by         Formulae 1A or 1B above.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic cross-sectional view illustrating a structure of an organic light-emitting device according to an exemplary embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present exemplary embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the exemplary embodiments are merely described below, by referring to the figures, to explain aspects. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

It will be understood that when an element is referred to as being “on” another element, it can be directly in contact with the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present.

It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the present embodiments.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

“About” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system). For example, “about” can mean within one or more standard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to cross section illustrations that are schematic illustrations of idealized embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear features. Moreover, sharp angles that are illustrated may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the present claims.

According to an aspect, there is provided a carbazole compound represented by Formulae 1A or 1B below:

In Formulae 1A and 1B,

-   -   A may be -(L₁)_(a1)-(E₁)_(b1),     -   L₁ may be selected from a substituted or unsubstituted C₆-C₆₀         arylene group, and a substituted or unsubstituted C₁-C₆₀         heteroarylene group;     -   E₁ may be a substituted or unsubstituted electron         transporting-cyclic group or a substituted or unsubstituted         carbazolyl group, each of which includes at least one         nitrogen (N) as a ring-forming atom;     -   a1 may be selected from integers of 1 to 3;     -   b1 may be 1 or 2, provided that when b1 is 2, two groups E₁ may         be each independently connected to L₁ and may be identical to or         different from each other;     -   R₁ may be selected from a deuterium atom, —F, —Cl, —Br, —I, a         hydroxyl group, a cyano group, a nitro group, an amino group, an         amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid group or a salt thereof, a sulfonic acid group         or a salt thereof, a phosphoric acid group or a salt thereof, a         substituted or unsubstituted C₁-C₂₀ alkyl group, a substituted         or unsubstituted C₂-C₂₀ alkenyl group, a substituted or         unsubstituted C₂-C₂₀ alkynyl group, and a substituted or         unsubstituted C₁-C₂₀ alkoxy group;     -   R₂ to R₄ may be each independently selected from a deuterium         atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro         group, an amino group, an amidino group, a hydrazine group, a         hydrazone group, a carboxylic acid group or a salt thereof, a         sulfonic acid group or a salt thereof, a phosphoric acid group         or a salt thereof, a substituted or unsubstituted C₁-C₂₀ alkyl         group, a substituted or unsubstituted C₂-C₂₀ alkenyl group, a         substituted or unsubstituted C₂-C₂₀ alkynyl group, a substituted         or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or         unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or         unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or         unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or         unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted         C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀         arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl         group, a substituted or unsubstituted monovalent non-aromatic         condensed polycyclic group, a substituted or unsubstituted         monovalent non-aromatic condensed heteropolycyclic group,         —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), and —B(Q₁₆)(Q₁₇);     -   c1 to c3 may be each independently 1 or 2;     -   at least one of substituents of the substituted C₆-C₆₀ arylene         group, the substituted C₁-C₆₀ heteroarylene group, the         substituted electron transporting-cyclic group, the substituted         carbazolyl group, the substituted C₁-C₂₀ alkyl group, the         substituted C₂-C₂₀ alkenyl group, the substituted C₂-C₂₀ alkynyl         group, the substituted C₃-C₁₀ cycloalkyl group, the substituted         C₁-C₁₀ heterocycloalkyl group, the substituted C₃-C₁₀         cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenyl         group, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀         aryloxy group, the substituted C₆-C₆₀ arylthio group, the         substituted C₁-C₆₀ heteroaryl group, the substituted monovalent         non-aromatic condensed polycyclic group, and the substituted         monovalent non-aromatic condensed heteropolycyclic group may be         selected from     -   a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a         C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, and a C₁-C₂₀         alkoxy group;     -   a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl         group, and a C₁-C₂₀ alkoxy group, each substituted with at least         one of a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a         cyano group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl         group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl         group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a         C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀         heteroaryl group, a monovalent non-aromatic condensed polycyclic         group, a monovalent non-aromatic condensed heteropolycyclic         group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), and —B(Q₂₆)(Q₂₇);     -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic         condensed polycyclic group, and a monovalent non-aromatic         condensed heteropolycyclic group;     -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic         condensed polycyclic group, and a monovalent non-aromatic         condensed heteropolycyclic group, each substituted with at least         one of a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a         cyano group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a         C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, a C₁-C₂₀ alkoxy         group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl         group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl         group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀         arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent         non-aromatic condensed polycyclic group, a monovalent         non-aromatic condensed heteropolycyclic group, —N(Q₃₁)(Q₃₂),         —Si(Q₃₃)(Q₃₄)(Q₃₅), and —B(Q₃₆)(Q₃₇); and     -   —N(Q₄₁)(Q₄₂), —Si(Q₄₃)(Q₄₄)(Q₄₅) and —B(Q₄₆)(Q₄₇), and     -   Q₁₁ to Q₁₇, Q₂₁ to Q₂₇, Q₃₁ to Q₃₇, and Q₄₁ to Q₄₇ may be each         independently selected from a hydrogen, a C₁-C₂₀ alkyl group, a         C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, a C₁-C₂₀ alkoxy         group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl         group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl         group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a         monovalent non-aromatic condensed polycyclic group, and a         monovalent non-aromatic condensed heteropolycyclic group.

In Formulae 1A and 1B,

-   -   L₁ may be selected from a phenylene group, a pentalenylene         group, an indenylene group, a naphthylene group, an azulenylene         group, a heptalenylene group, an indacenylene group, an         acenaphthylene group, a fluorenylene group, a spiro-fluorenylene         group, a phenalenylene group, a phenanthrenylene group, an         anthracenylene group, a fluoranthrenylene group, a         triphenylenylene group, a pyrenylene group, a chrysenylene         group, a naphthacenylene group, a picenylene group, a         perylenylene group, a pentaphenylene group, a hexacenylene         group, a pyrrolylene group, an imidazolylene group, a         pyrazolylene group, a pyridinylene group, a pyrazinylene group,         a pyrimidinylene group, a pyridazinylene group, an isoindolylene         group, an indolylene group, an indazolylene group, a purinylene         group, a quinolinylene group, an isoquinolinylene group, a         benzoquinolinylene group, a phthalazinylene group, a         naphthyridinylene group, a quinoxalinylene group, a         quinazolinylene group, a cinnolinylene group, a carbazolylene         group, a phenanthridinylene group, an acridinylene group, a         phenanthrolinylene group, a phenazinylene group, a         benzooxazolylene group, a benzoimidazolylene group, a furanylene         group, a benzofuranylene group, a thiophenylene group, a         benzothiophenylene group, a thiazolylene group, an         isothiazolylene group, a benzothiazolylene group, an         isoxazolylene group, an oxazolylene group, a triazolylene group,         a tetrazolylene group, an oxadiazolylene group, a triazinylene         group, a dibenzofuranylene group, a dibenzothiophenylene group,         a benzocarbazolylene group, a dibenzocarbazolylene group, an         imidazopyrimidinylene group, and an imidazopyridinylene group;         and     -   a phenylene group, a pentalenylene group, an indenylene group, a         naphthylene group, an azulenylene group, a heptalenylene group,         an indacenylene group, an acenaphthylene group, a fluorenylene         group, a spiro-fluorenylene group, a phenalenylene group, a         phenanthrenylene group, an anthracenylene group, a         fluoranthrenylene group, a triphenylenylene group, a pyrenylene         group, a chrysenylene group, a naphthacenylene group, a         picenylene group, a perylenylene group, a pentaphenylene group,         a hexacenylene group, a pyrrolylene group, an imidazolylene         group, a pyrazolylene group, a pyridinylene group, a         pyrazinylene group, a pyrimidinylene group, a pyridazinylene         group, an isoindolylene group, an indolylene group, an         indazolylene group, a purinylene group, a quinolinylene group,         an isoquinolinylene group, a benzoquinolinylene group, a         phthalazinylene group, a naphthyridinylene group, a         quinoxalinylene group, a quinazolinylene group, a cinnolinylene         group, a carbazolylene group, a phenanthridinylene group, an         acridinylene group, a phenanthrolinylene group, a phenazinylene         group, a benzooxazolylene group, a benzoimidazolylene group, a         furanylene group, a benzofuranylene group, a thiophenylene         group, a benzothiophenylene group, a thiazolylene group, an         isothiazolylene group, a benzothiazolylene group, an         isoxazolylene group, an oxazolylene group, a triazolylene group,         a tetrazolylene group, an oxadiazolylene group, a triazinylene         group, a dibenzofuranylene group, a dibenzothiophenylene group,         a benzocarbazolylene group, a dibenzocarbazolylene group, an         imidazopyrimidinylene group, and an imidazopyridinylene group,         each substituted with at least one of a deuterium atom, —F, —Cl,         —Br, —I, a hydroxyl group, a cyano group, a nitro group, an         amino group, an amidino group, a hydrazine group, a hydrazone         group, a carboxylic acid group or a salt thereof, a sulfonic         acid group or a salt thereof, a phosphoric acid group or a salt         thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a C₆-C₂₀         aryl group, and a C₁-C₆₀ heteroaryl group.

In some embodiments, L₁ in Formulae 1A and 1B may be selected from

-   -   a phenylene group, a naphthylene group, a phenalenylene group, a         phenanthrenylene group, an anthracenylene group, a pyrrolylene         group, a pyridinylene group, a pyrazinylene group, a         pyrimidinylene group, a pyridazinylene group, an isoindolylene         group, an indolylene group, a furanylene group, a         benzofuranylene group, a thiophenylene group, a         benzothiophenylene group, and a triazinylene group; and     -   a phenylene group, a naphthylene group, a phenalenylene group, a         phenanthrenylene group, an anthracenylene group, a pyrrolylene         group, a pyridinylene group, a pyrazinylene group, a         pyrimidinylene group, a pyridazinylene group, an isoindolylene         group, an indolylene group, a furanylene group, a         benzofuranylene group, a thiophenylene group, a         benzothiophenylene group, and a triazinylene group, each         substituted with at least one of a deuterium atom, —F, —Cl, —Br,         —I, a hydroxyl group, a cyano group, a nitro group, an amino         group, an amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid group or a salt thereof, a sulfonic acid group         or a salt thereof, a phosphoric acid group or a salt thereof, a         C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a         naphthyl group, an anthracenyl group, a pyrenyl group, a         phenanthrenyl group, a fluorenyl group, a carbazolyl group, a         benzocarbazolyl group, a dibenzocarbazolyl group, a pyridinyl         group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl         group, a triazinyl group, a quinolinyl group, an isoquinolinyl         group, a phthalazinyl group, a quinoxalinyl group, a cinnolinyl         group, and a quinazolinyl group; and     -   a1 may be 1 or 2.

In some other embodiments, (L₁)_(a1) in Formulae 1A and 1B may be represented by one of Formulae 2A to 2F below:

In Formulae 2A to 2F,

-   -   Z₁₁ and Z₁₂ may be each independently selected from a deuterium         atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro         group, an amino group, an amidino group, a hydrazine group, a         hydrazone group, a carboxylic acid group or a salt thereof, a         sulfonic acid group or a salt thereof, a phosphoric acid group         or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group,         a phenyl group, a naphthyl group, an anthracenyl group, a         pyrenyl group, a phenanthrenyl group, a fluorenyl group, a         carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl         group, a pyridinyl group, a pyrimidinyl group, a pyrazinyl         group, a pyridazinyl group, a triazinyl group, a quinolinyl         group, an isoquinolinyl group, a phthalazinyl group, a         quinoxalinyl group, a cinnolinyl group, and a quinazolinyl         group;     -   p1 and p2 may be each independently an integer of 0 to 4;     -   p3 may be an integer of 0 to 3; and     -   * and *′ may each independently indicate a binding site to a         neighboring group or atom, wherein *′ may indicate a binding         site to E₁.

For example, (L₁)_(a1) in Formulae 1A and 1B may be represented by one of Formulae 3A to 3G below:

In an embodiment, E₁ in Formulae 1A and 1B may be selected from a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, a thiazolyl group, an isothiazolyl group, a benzothiazolyl group, an isoxazolyl group, an oxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a carbazolyl group, an imidazopyrimidinyl group, and an imidazopyridinyl group; and

-   -   a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a         pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a         pyridazinyl group, an isoindolyl group, an indolyl group, an         indazolyl group, a purinyl group, a quinolinyl group, an         isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl         group, a naphthyridinyl group, a quinoxalinyl group, a         quinazolinyl group, a cinnolinyl group, a phenanthridinyl group,         an acridinyl group, a phenanthrolinyl group, a phenazinyl group,         a benzoimidazolyl group, a thiazolyl group, an isothiazolyl         group, a benzothiazolyl group, an isoxazolyl group, an oxazolyl         group, a triazolyl group, a tetrazolyl group, an oxadiazolyl         group, a triazinyl group, a carbazolyl group, an         imidazopyrimidinyl group, and an imidazopyridinyl group, each         substituted with at least one Ar₁,     -   wherein Ar₁ may be selected from     -   a phenyl group, a pentalenyl group, an indenyl group, a naphthyl         group, an azulenyl group, a heptalenyl group, an indacenyl         group, an acenaphthyl group, a fluorenyl group, a         spiro-fluorenyl group, a phenalenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthrenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         naphthacenyl group, a picenyl group, a perylenyl group, a         pentaphenyl group, a hexacenyl group, a pyrrolyl group, an         imidazolyl group, a pyrazolyl group, a pyridinyl group, a         pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an         isoindolyl group, an indolyl group, an indazolyl group, a         purinyl group, a quinolinyl group, an isoquinolinyl group, a         benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl         group, a carbazolyl group, a phenanthridinyl group, an acridinyl         group, a phenanthrolinyl group, a phenazinyl group, a         benzoxazolyl group, a benzoimidazolyl group, a furanyl group, a         benzofuranyl group, a thiophenyl group, a benzothiophenyl group,         a thiazolyl group, an isothiazolyl group, a benzothiazolyl         group, an isoxazolyl group, an oxazolyl group, a triazolyl         group, a tetrazolyl group, an oxadiazolyl group, a triazinyl         group, a dibenzofuranyl group, a dibenzothiophenyl group, a         benzocarbazolyl group, a dibenzocarbazolyl group, an         imidazopyrimidinyl group, and an imidazopyridinyl group; and     -   a phenyl group, a pentalenyl group, an indenyl group, a naphthyl         group, an azulenyl group, a heptalenyl group, an indacenyl         group, an acenaphthyl group, a fluorenyl group, a         spiro-fluorenyl group, a phenalenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthrenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         naphthacenyl group, a picenyl group, a perylenyl group, a         pentaphenyl group, a hexacenyl group, a pyrrolyl group, an         imidazolyl group, a pyrazolyl group, a pyridinyl group, a         pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an         isoindolyl group, an indolyl group, an indazolyl group, a         purinyl group, a quinolinyl group, an isoquinolinyl group, a         benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl         group, a carbazolyl group, a phenanthridinyl group, an acridinyl         group, a phenanthrolinyl group, a phenazinyl group, a         benzoxazolyl group, a benzoimidazolyl group, a furanyl group, a         benzofuranyl group, a thiophenyl group, a benzothiophenyl group,         a thiazolyl group, an isothiazolyl group, a benzothiazolyl         group, an isoxazolyl group, an oxazolyl group, a triazolyl         group, a tetrazolyl group, an oxadiazolyl group, a triazinyl         group, a dibenzofuranyl group, a dibenzothiophenyl group, a         benzocarbazolyl group, a dibenzocarbazolyl group, an         imidazopyrimidinyl group, and an imidazopyridinyl group, each         substituted with at least one of a deuterium atom, —F, —Cl, —Br,         —I, a hydroxyl group, a cyano group, a nitro group, an amino         group, an amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid group or a salt thereof, a sulfonic acid group         or a salt thereof and a phosphoric acid group or a salt thereof,         a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl         group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group,         an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a         fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a pyridinyl group, a pyrimidinyl group,         a pyrazinyl group, a pyridazinyl group, a triazinyl group, a         quinolinyl group, an isoquinolinyl group, a phthalazinyl group,         a quinoxalinyl group, a cinnolinyl group, and a quinazolinyl         group.

In an embodiment, E₁ in Formulae 1A and 1B may be represented by one of Formulae 4A to 4C below:

In Formulae 4A to 4C,

-   -   Ar¹ may be selected from a phenyl group, a naphthyl group, an         anthracenyl group, a pyrenyl group, a phenanthrenyl group, a         fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a pyridinyl group, a pyrimidinyl group,         a pyrazinyl group, a pyridazinyl group, a triazinyl group, a         quinolinyl group, an isoquinolinyl group, a phthalazinyl group,         a quinoxalinyl group, a cinnolinyl group, and a quinazolinyl         group;     -   Z₂₁ may be selected from a C₁-C₂₀ alkyl group and a C₁-C₂₀         alkoxy group;     -   a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted         with at least one of a deuterium atom, —F, —Cl, —Br, —I, a         hydroxyl group, a cyano group, a nitro group, an amino group, an         amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid group or a salt thereof, a sulfonic acid group         or a salt thereof, a phosphoric acid group or a salt thereof, a         phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl         group, a phenanthrenyl group, a fluorenyl group, a carbazolyl         group, a benzocarbazolyl group, a dibenzocarbazolyl group, a         pyridinyl group, a pyrimidinyl group, a triazinyl group, a         quinolinyl group, an isoquinolinyl group, and a quinazolinyl         group;     -   q1 may be an integer of 0 to 3;     -   q2 may be an integer of 0 to 2;     -   q3 may be an integer of 0 to 4; and     -   * may indicate a binding site to a neighboring group or atom.

For example, in Formulae 4A to 4C, Ar¹ may be a phenyl group, q1 and q2 may be each 2, and q3 and q4 may be each 0.

In an embodiment, E₁ in Formulae 1A and 1B may be represented by one of Formulae 5A to 5C below:

In Formulae 5A to 5C, * may indicate a binding site to a neighboring group or atom.

In Formulae 1A and 1B,

-   -   R₁ may be selected from     -   a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group;     -   a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted         with at least one of a deuterium atom, —F, —Cl, —Br, —I, a         hydroxyl group, a cyano group, a nitro group, an amino group, an         amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid group or a salt thereof, a sulfonic acid group         or a salt thereof, a phosphoric acid group or a salt thereof, a         phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl         group, a phenanthrenyl group, a fluorenyl group, a carbazolyl         group, a benzocarbazolyl group, a dibenzocarbazolyl group, a         pyridinyl group, a pyrimidinyl group, a triazinyl group, a         quinolinyl group, an isoquinolinyl group, and a quinazolinyl         group.

For example, R₁ may be selected from a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a pentoxy group.

In Formulae 1A and 1B,

-   -   R₂ to R₄ may be each independently selected from     -   a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a         C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, and a C₁-C₂₀         alkoxy group;     -   a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl         group, and a C₁-C₂₀ alkoxy group, each substituted with at least         one of a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a         cyano group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a phenyl group, a         naphthyl group, an anthracenyl group, a pyrenyl group, a         phenanthrenyl group, a fluorenyl group, a carbazolyl group, a         benzocarbazolyl group, a dibenzocarbazolyl group, a pyridinyl         group, a pyrimidinyl group, a triazinyl group, a quinolinyl         group, an isoquinolinyl group, and a quinazolinyl group;     -   a phenyl group, a pentalenyl group, an indenyl group, a naphthyl         group, an azulenyl group, a heptalenyl group, an indacenyl         group, an acenaphthyl group, a fluorenyl group, a         spiro-fluorenyl group, a phenalenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthrenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         naphthacenyl group, a picenyl group, a perylenyl group, a         pentaphenyl group, a hexacenyl group, a pyrrolyl group, an         imidazolyl group, a pyrazolyl group, a pyridinyl group, a         pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an         isoindolyl group, an indolyl group, an indazolyl group, a         purinyl group, a quinolinyl group, an isoquinolinyl group, a         benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl         group, a carbazolyl group, a phenanthridinyl group, an acridinyl         group, a phenanthrolinyl group, a phenazinyl group, a         benzoxazolyl group, a benzoimidazolyl group, a furanyl group, a         benzofuranyl group, a thiophenyl group, a benzothiophenyl group,         a thiazolyl group, an isothiazolyl group, a benzothiazolyl         group, an isoxazolyl group, an oxazolyl group, a triazolyl         group, a tetrazolyl group, an oxadiazolyl group, a triazinyl         group, a dibenzofuranyl group, a dibenzothiophenyl group, a         benzocarbazolyl group, a dibenzocarbazolyl group, an         imidazopyridinyl group, and an imidazopyridinyl group;     -   a phenyl group, a pentalenyl group, an indenyl group, a naphthyl         group, an azulenyl group, a heptalenyl group, an indacenyl         group, an acenaphthyl group, a fluorenyl group, a         spiro-fluorenyl group, a phenalenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthrenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         naphthacenyl group, a picenyl group, a perylenyl group, a         pentaphenyl group, a hexacenyl group, a pyrrolyl group, an         imidazolyl group, a pyrazolyl group, a pyridinyl group, a         pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an         isoindolyl group, an indolyl group, an indazolyl group, a         purinyl group, a quinolinyl group, an isoquinolinyl group, a         benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl         group, a carbazolyl group, a phenanthridinyl group, an acridinyl         group, a phenanthrolinyl group, a phenazinyl group, a         benzoxazolyl group, a benzoimidazolyl group, a furanyl group, a         benzofuranyl group, a thiophenyl group, a benzothiophenyl group,         a thiazolyl group, an isothiazolyl group, a benzothiazolyl         group, an isoxazolyl group, an oxazolyl group, a triazolyl         group, a tetrazolyl group, an oxadiazolyl group, a triazinyl         group, a dibenzofuranyl group, a dibenzothiophenyl group, a         benzocarbazolyl group, a dibenzocarbazolyl group, an         imidazopyrimidinyl group, and an imidazopyridinyl group, each         substituted with at least one of a deuterium atom, —F, —Cl, —Br,         —I, a hydroxyl group, a cyano group, a nitro group, an amino         group, an amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid group or a salt thereof, a sulfonic acid group         or a salt thereof, a phosphoric acid group or a salt thereof, a         C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl         group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group,         an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a         fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a pyridinyl group, a pyrimidinyl group,         a pyrazinyl group, a pyridazinyl group, a triazinyl group, a         quinolinyl group, an isoquinolinyl group, a phthalazinyl group,         a quinoxalinyl group, a cinnolinyl group, and a quinazolinyl         group; and     -   —N(Q₁₃)(Q₁₄) and —Si(Q₁₅)(Q₁₆)(Q₁₇), and     -   Q₁₃ to Q₁₇ may be each independently selected from a hydrogen, a         C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a         naphthyl group, an anthracenyl group, a pyrenyl group, a         phenanthrenyl group, a fluorenyl group, a carbazolyl group, a         benzocarbazolyl group, a dibenzocarbazolyl group, a pyridinyl         group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl         group, a triazinyl group, a quinolinyl group, an isoquinolinyl         group, a phthalazinyl group, a quinoxalinyl group, a cinnolinyl         group, and a quinazolinyl group.

In an exemplary embodiment, R₂ to R₄ may be each independently selected from

-   -   a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a         C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, and a C₁-C₂₀         alkoxy group;     -   a phenyl group, a naphthyl group, a pyridinyl group, and a         naphthyridinyl group;     -   a phenyl group, a naphthyl group, a pyridinyl group, and a         naphthyridinyl group, each substituted with at least one of a         deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a         C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, a C₁-C₂₀ alkoxy         group, a phenyl group, a naphthyl group, an anthracenyl group, a         pyrenyl group, a phenanthrenyl group, a fluorenyl group, a         carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl         group, a pyridinyl group, a pyrimidinyl group, a pyrazinyl         group, a pyridazinyl group, a triazinyl group, a quinolinyl         group, an isoquinolinyl group, a phthalazinyl group, a         quinoxalinyl group, a cinnolinyl group, and a quinazolinyl         group; and     -   —Si(Q₁₅)(Q₁₆)(Q₁₇),     -   wherein Q₁₅ to Q₁₇ may be each independently selected from a         hydrogen, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl         group, a naphthyl group, an anthracenyl group, a pyrenyl group,         a phenanthrenyl group, a fluorenyl group, a carbazolyl group, a         benzocarbazolyl group, a dibenzocarbazolyl group, a pyridinyl         group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl         group, a triazinyl group, a quinolinyl group, an isoquinolinyl         group, a phthalazinyl group, a quinoxalinyl group, a cinnolinyl         group, and a quinazolinyl group.

For example, R₂ may be selected from a methyl group and an ethyl group;

-   -   R₃ to R₄ may be each independently selected from a methyl group,         an ethyl group, an n-propyl group, an iso-propyl group, an         n-butyl group, an iso-butyl group, a sec-butyl group, a         tert-butyl group, an n-pentyl group, an iso-pentyl group, a         sec-pentyl group, a tert-pentyl group, a methoxy group, an         ethoxy group, a propoxy group, a butoxy group, and a pentoxy         group; and     -   optionally, at least one of R₃ to R₄ may be each independently         selected from fluorine and a C₁-C₂₀ alkoxy group.

The carbazole compound of Formulae 1A or 1B may include at least one of Compounds 1 to 30 below, but the carbazole compound is not limited thereto:

Optionally, the carbazole compound of an exemplary embodiment of the present inventive concept may include a substituent, e.g., at least one of fluorine and a C₁-C₂₀ alkoxy group. For example, several hydrogens of Compounds of exemplary embodiments above may be substituted with fluorine or an alkoxy group.

The carbazole compound of an exemplary embodiment of the present inventive concept may have charge transport capability provided by a substituent including a charge-transporting group that is introduced to the 1-position of the carbazolyl group (or pyrido-carbazolyl group). In addition, because the position of the substituent including a charge-transporting group which is introduced to the carbazolyl group (or pyrido-carbazolyl group) is the 1-position rather than the N-, 2-, or 3-positions, a large energy band gap in a triplet state may be obtained.

In addition, an organic light-emitting device including the carbazole compound that has both hole-transporting capability and electron-transporting capability may ensure carrier balance between holes and electrons. Thus, due to the presence of the carbazole compound, an organic light-emitting device may have improved emission efficiency and lifespan.

A method of synthesizing the carbazole compound of Formula 1 above may be understood by referring to Synthesis Examples that will be provided below.

According to an aspect, there is provided a carbazole compound represented by Formulae 1A or 1B suitable as a host of an organic layer, e.g., an emission layer included in the organic layer, of an organic light-emitting device. According to another aspect, there is provided an organic light-emitting device including:

-   -   a first electrode;     -   a second electrode; and     -   an organic layer disposed between the first electrode and the         second electrode, wherein the organic layer includes an emission         layer and at least one carbazole compound represented by         Formulae 1A or 1B.

The organic light-emitting device includes an organic layer that includes the carbazole compound represented by Formulae 1A or 1B, and accordingly, the organic light-emitting device may have low driving voltage, high efficiency, high luminance, and long lifespan characteristics.

The carbazole compound represented by Formulae 1A or 1B may be used between a pair of electrodes of the organic light-emitting device. For example, the carbazole compound may be included in at least one of the emission layer, a hole transport region (for example, including at least one of a hole injection layer, a hole transport layer, and an electron blocking layer) formed between the first electrode and the emission layer, and an electron transport region (for example, including at least one of a hole blocking layer, an electron transport layer, and an electron injection layer) formed between the emission layer and the second electrode. For example, the carbazole compound represented by Formulae 1A or 1B may be included in the emission layer. Here, the emission layer may further include a dopant, and the carbazole compound included in the emission layer may function as a host. The emission layer may be a green emission layer emitting green light or a red emission layer emitting red light. The dopant may be a phosphorescent dopant.

The expression “(an organic layer) includes at least one of carbazole compounds” used herein refers to “(an organic layer) includes one carbazole compound of Formulae 1A or 1B or two or more different carbazole compounds of Formulae 1A or 1B”.

For example, the organic layer may include, as the carbazole compound, only Compound 1. In this regard, Compound 1 may be situated in the emission layer of the organic light-emitting device. Alternatively, the organic layer may include, as the carbazole compound, Compound 1 and Compound 2. In this regard, Compound 1 and Compound 2 may be situated in either an identical layer (for example, Compound 1 and Compound 2 all may be situated in an emission layer), or different layers.

The first electrode may be an anode that is a hole injection electrode, and the second electrode may be a cathode that is an electron injection electrode. Alternatively, the first electrode may be a cathode that is an electron injection electrode, and the second electrode may be a anode that is a hole injection electrode.

For example, the first electrode may be an anode, the second electrode may be a cathode, and the organic layer may include:

-   -   i) a hole transport region that is formed between the first         electrode (i.e., an anode) and the emission layer, wherein the         hole transport region includes at least one of a hole injection         layer, a hole transport layer, and an electron blocking layer,         and     -   ii) an electron transport region that is formed between the         emission layer and the second electrode (i.e., a cathode),         wherein the electron transport region includes at least one of a         hole blocking layer, an electron transport layer, and an         electron injection layer.

The term “organic layer” used herein refers to a single layer and/or a plurality of layers disposed between the first electrode and the second electrode of the organic light-emitting device. A material included in the “organic layer” may include a metal-containing organometallic complex in addition to an organic compound.

FIG. 1 illustrates a schematic cross-sectional view of an organic light-emitting device 100 according to an exemplary embodiment. Hereinafter, the structure of an organic light-emitting device according to an exemplary embodiment and a method of manufacturing an organic light-emitting device according to an exemplary embodiment will be described in connection with FIG. 1.

In FIG. 1, the organic light-emitting device 100 includes a substrate 110, a first electrode 120 disposed on the substrate 110, a hole injection layer 130 disposed on the first electrode 120, a hole transport layer 140 disposed on the hole injection layer 130, an emission layer 150 disposed on the hole transport layer 140, an electron transport layer 160 disposed on the emission layer 150, an electron injection layer 170 disposed on the electron transport layer 160, and a second electrode 180 disposed on the electron injection layer 170.

The carbazole compound used herein may be included in one or more layers disposed between the first electrode 120 and the second electrode 180 of the organic light-emitting device 100. The carbazole compound may be included as a host material in the emission layer 150.

For use as the substrate 110, any suitable substrate that is used in general organic light-emitting devices may be used, and the substrate 110 may be a glass substrate, a semiconductor substrate, a transparent plastic substrate.

The first electrode 120 may be, for example, an anode, and may be formed on the 110 by using deposition or sputtering method. In detail, the first electrode 120 may be formed as a transmissive electrode by using materials with a high work function, such as a metal, an alloy, or a conductive compound. The first electrode 120 may be formed as, for example, a reflective electrode by using indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO₂), or zinc oxide (ZnO), each with transparency and excellent conductivity. Alternatively, the first electrode 120 may be formed as a semi-transmissive electrode by using magnesium (Mg), aluminum, or the like.

The hole injection layer 130 is a functional layer that facilitates hole injection from the first electrode 120, and may be formed on the first electrode 120 by using various methods, such as vacuum deposition, spin coating, ink-jet printing, or the like. In addition, the hole injection layer 130 may be formed to a thickness in a range of about 10 nanometers (nm) to 1,000 nm, and for example, about 10 nm to about 100 nm.

In addition, the hole injection layer 130 may be formed by using a material known in the art, such as N,N′-diphenyl-N,N′-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4′-diamine (DNTPD), a phthalocyanine compound, such as phthalocyanine, 4,4′,4″-tris(3-methylphenylphenylamino)triphenyl amine (m-MTDATA), N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPB), 4,4′,4″-tris{N,N-diphenyl amino}triphenyl amine (TDATA), 4,4′,4″-tris(N,N-2-naphthylphenylamino)triphenylamine (2-TNATA), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), or polyaniline/camphorsulfonic acid (PANI/CSA), polyaniline/poly(4-styrenesulfonate):polyaniline (PANI/PSS).

The hole transport layer 140 is a layer including a hole-transporting material that is capable of transporting a hole, and may be formed on the hole injection layer 130 by using various methods, such as vacuum deposition, spin coating, ink-jet printing, or the like. In addition, the hole transport layer 140 may be formed to a thickness in a range of about 5 nm to about 200 nm, and for example, about 10 nm to about 150 nm. In addition, the hole transport layer 140 may be formed by using a suitable hole-transporting material, such as N-phenylcarbazole, a carbazole derivative, such as polyvinyl carbazole, N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine (TPD), 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), 4,4′,4″-tris(N-carbazolyl)triphenylamine), N,N′-bis(naphthalene-2-yl)-N,N′-bis(phenyl)-benzidine (NPB), N,N′-bis(naphthalene-1-yl)-N,N′-bisphenyl)-benzidine), or N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)-2,2′-dimethylbenzidine (α-NPD).

The emission layer 150 is a layer emitting phosphorescent or fluorescent light, and may be formed on the hole transport layer 140 by using various methods, such as vacuum deposition, spin coating, ink-jet printing, or the like. In addition, the emission layer 150 may include a host material and a dopant material, and for example, may include, as a host material, the carbazole compound of an exemplary embodiment. In addition, the emission layer 150 may be formed to a thickness in a range of about 10 nm to about 100 nm, and for example, about 20 nm to about 60 nm.

In addition, the emission layer 150 may include other host materials, such as tris(8-quinolinorate)aluminum) (Alq₃), 4,4′-N,N′-dicarbazole-biphenyl (CBP), poly(n-vinylcarbazole) (PVK), 9,10-di(naphthalene-2-yl)anthracene (ADN), TCTA, 1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene (TPBI), 3-tert-butyl-9,10-di(naphth-2-yl)anthracene (TBADN), distyrylarylene (DSA), or 4,4′-bis(9-carbazole)-2,2′-dimethylbiphenyl (dmCBP).

In addition, the emission layer 150 may be an emission layer emitting a certain light color. For example, the emission layer 150 may be formed as a red emission layer, a green emission layer, and a blue emission layer. In addition, the carbazole compound of an exemplary embodiment may be suitable as a host material of a red emission layer and a green emission layer.

When the emission layer 150 is a blue emission layer, the blue emission layer may be formed by using a material known in the art, such as perylene and a derivative thereof, and an iridium (Ir) complex, e.g., bis[2-(4,6-difluorophenyl)pyridate]picolinateiridium(III) (Flrpic).

When the emission layer 150 is a red emission layer, examples of a material available as a red dopant known in the art may include rubrene and a derivative thereof, 4-(dicyanomethylene)-2-methyl-6-[p-(dimethylamino)styryl]-4H-pyran (DCM) and a derivative thereof, an Ir complex, such as bis(1-phenylisoquinoline)(acetylacetonate)iridium(III) (Ir(piq)₂(acac)), an osmium (Os) complex, and a platinum (Pt) complex.

When the emission layer 150 is a green emission layer, examples of a material available as a green dopant known in the art may include coumarin and a derivative thereof, and an Ir complex, such as tris(2-phenylpyridine)(iridium(III)(Ir(ppy)₃)).

The electron transport layer 160 is a layer including an electron-transporting material that is capable of transporting an electron, and may be formed on the emission layer 150 by using methods, such as vacuum deposition, spin coating, ink-jet printing, or the like. In addition, the electron transport layer 160 may be formed to a thickness in a range of about 10 nm to about 100 nm, and for example, about 15 nm to about 50 nm. In addition, the electron transport layer 160 may be formed by using an electron-transporting material known in the art, and examples of the electron-transporting material are a lithium (Li) complex, such as lithium quinolate (LiQ), a quinoline derivative, such as tris(8-quinolinato)aluminum (Alq₃), 1,2,4-triazole derivative (TAZ), bis(2-methyl-8-quinolinolato)-(p-phenylphenolato)-aluminum(BAlq), beryllium, and bis(benzoquinoline 10-olate) (BeBq₂).

The electron injection layer 170 is a functional layer that facilitates electron injection from the second electrode 180, and may be formed on the electron transport layer 160 by using vacuum deposition. In addition, the electron injection layer 170 may be formed to a thickness in a range of about 0.1 nm to about 10 nm, and for example, about 0.3 nm to about 9 nm.

In addition, the electron injection layer 170 may be formed by using a material known in the art, and examples of the material are lithium fluoride (LiF), sodium chloride (NaCl), cesium fluoride (CsF), lithium oxide (Li₂O), barium oxide (BaO).

The second electrode 180 may be, for example, a cathode, and may be formed on the electron injection layer 170 by using deposition or sputtering method. In detail, the second electrode 180 may be formed as a reflective electrode by using materials with a low work function, such as a metal, an alloy, or a conductive compound. The second electrode 180 may be formed of, for example, lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag). In addition, the second electrode 180 may be formed as a transmissive electrode by using indium tin oxide (ITO) or indium zinc oxide (IZO).

The structure of the organic light-emitting device 100 according to an exemplary embodiment is described, but the structure is not limited thereto. The organic light-emitting device 100 according to an exemplary embodiment may be fabricated by using other structures of organic light-emitting devices known in the art. For example, the organic light-emitting device 100 may not include one or more of the hole injection layer 130, the hole transport layer 140, the electron transport layer 160, and the electron injection layer 170. The layers of the organic light-emitting device 100 may be each formed in a single-layer structure or a multi-layer structure including a plurality of layers.

Furthermore, the organic light-emitting device 100 may include a hole blocking layer between the hole transport layer 140 and the emission layer 150 to help prevent diffusion of triplet excitons or holes into the electron transport layer 160. The hole blocking layer may be formed of, for example, an oxadiazole derivative, a triazole derivative, or a phenanthroline derivative.

A C₁-C₂₀ alkyl group as used herein refers to a linear or branched aliphatic hydrocarbon monovalent group having 1 to 20 carbon atoms. Detailed examples thereof are a methyl group, an ethyl group, a propyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an iso-amyl group, and a hexyl group. A C₁-C₂₀ alkylene group as used herein refers to a divalent group having the same structure as the C₁-C₂₀ alkyl group.

A C₁-C₂₀ alkoxy group as used herein refers to a monovalent group represented by —OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl). Detailed examples thereof are a methoxy group, an ethoxy group, and an isopropyloxy group.

A C₂-C₂₀ alkenyl group as used herein refers to a hydrocarbon group formed by substituting at least one carbon double bond in the middle or at the terminal of the C₂-C₂₀ alkyl group. Detailed examples thereof are an ethenyl group, a propenyl group, and a butenyl group. A C₂-C₂₀ alkenylene group as used herein refers to a divalent group having the same structure as the C₂-C₂₀ alkenyl group.

A C₂-C₂₀ alkynyl group as used herein refers to a hydrocarbon group formed by substituting at least one carbon triple bond in the middle or at the terminal of the C₂-C₂₀ alkyl group. Detailed examples thereof are an ethynyl group and a propynyl group. A C₂-C₂₀ alkynylene group as used herein refers to a divalent group having the same structure as the C₂-C₂₀ alkynyl group.

A C₃-C₁₀ cycloalkyl group as used herein refers to a monovalent hydrocarbon monocyclic group having 3 to 10 carbon atoms. Detailed examples thereof are a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. A C₃-C₁₀ cycloalkylene group as used herein refers to a divalent group having the same structure as the C₃-C₁₀ cycloalkyl group.

A C₁-C₁₀ heterocycloalkyl group as used herein refers to a monovalent monocyclic group having at least one heteroatom selected from N, O, P, and S as a ring-forming atom and 1 to 10 carbon atoms. Detailed examples thereof are a tetrahydrofuranyl group and a tetrahydrothiophenyl group. A C₁-C₁₀ heterocycloalkylene group as used herein refers to a divalent group having the same structure as the C₁-C₁₀ heterocycloalkyl group.

A C₃-C₁₀ cycloalkenyl group as used herein refers to a monovalent monocyclic group that has 3 to 10 carbon atoms and at least one double bond in the ring thereof, and which is not aromatic. Detailed examples thereof are a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. A C₃-C₁₀ cycloalkenylene group as used herein refers to a divalent group having the same structure as the C₃-C₁₀ cycloalkenyl group.

A C₁-C₁₀ heterocycloalkenyl group as used herein refers to a monovalent monocyclic group that has at least one heteroatom selected from N, O, P, and S as a ring-forming atom, 1 to 10 carbon atoms, and at least one double bond in its ring. Detailed examples of the C₁-C₁₀ heterocycloalkenyl group are a 2,3-dihydrofuranyl group and a 2,3-dihydrothiophenyl group. A C₁-C₁₀ heterocycloalkenylene group as used herein refers to a divalent group having the same structure as the C₁-C₁₀ heterocycloalkenyl group.

A C₆-C₆₀ aryl group as used herein refers to a monovalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms, and a C₆-C₆₀ arylene group used herein refers to a divalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. Detailed examples of the C₆-C₆₀ aryl group are a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, and a chrysenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀ arylene group each include two or more rings, the rings may be fused to each other.

A C₁-C₆₀ heteroaryl group as used herein refers to a monovalent group having a carbocyclic aromatic system that has at least one heteroatom selected from N, O, P, and S as a ring-forming atom, and 1 to 60 carbon atoms. A C₁-C₆₀ heteroarylene group as used herein refers to a divalent group having a carbocyclic aromatic system that has at least one heteroatom selected from N, O, P, and S as a ring-forming atom, and 1 to 60 carbon atoms. Detailed examples of the C₁-C₆₀ heteroaryl group are a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, and an isoquinolinyl group. When the C₁-C₆₀ heteroaryl group and the C₁-C₆₀ heteroarylene group each include two or more rings, the rings may be fused to each other.

A C₆-C₆₀ aryloxy group as used herein indicates —OA₁₀₂ (wherein A₁₀₂ is the C₆-C₆₀ aryl group), and a C₆-C₆₀ arylthio group as used herein indicates —SA₁₀₃ (wherein A₁₀₃ is the C₆-C₆₀ aryl group).

A monovalent non-aromatic condensed polycyclic group (e.g., a group having 8 to 60 carbon atoms) as used herein refers to a monovalent group that has two or more rings condensed to each other, has carbon atoms only as a ring-forming atom, and which is non-aromatic in the entire molecular structure. A detailed example of the monovalent non-aromatic condensed polycyclic group is a fluorenyl group. A divalent non-aromatic condensed polycyclic group as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed polycyclic group.

A monovalent non-aromatic condensed heteropolycyclic group (e.g., a group having 2 to 60 carbon atoms) as used herein refers to a monovalent group that has two or more rings condensed to each other, has heteroatoms as a ring-forming atom selected from N, O, P, and S, in addition to C, and which is non-aromatic in the entire molecular structure. A detailed example of the monovalent non-aromatic condensed heteropolycyclic group is a carbazolyl group. A divalent non-aromatic condensed heteropolycyclic group as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed heteropolycyclic group.

Hereinafter, the compounds and the organic light-emitting device according to exemplary embodiments are described in detail with reference to Synthesis Examples and Examples, but are not limited thereto. The wording “‘B’ was used instead of ‘A’” used in describing Synthesis Examples means that a molar equivalent of ‘A’ was identical to a molar equivalent of ‘B’.

Synthesis Example

Compound 1 and Compound 19 were synthesized by a Suzuki-Miyaura cross-coupling reaction.

Synthesis Example 1 Synthesis of Compound 1

In a reaction container, 500 milligrams (mg) (1.29 millimoles (mmol)) of Compound A, 326 mg (1.3 mmol) of bis(pinacolato)diboron ((Bpin)₂), 252 mg (2.6 mmol) of potassium acetate (KOAc), and 105 mg (0.13 mmol) of [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II).dichloromethane (Pd(Dppf)Cl₂.CH₂Cl₂) were dissolved in 10 milliliters (mL) of 1,4-dioxane. The mixed solution was heated and stirred at a temperature of 90° C. The reaction solution was extracted with ethyl acetate (EtOAc). The extracted material was purified by column chromatography, thereby obtaining 486 mg of Compound B.

In a reaction container, 100 mg (0.55 mmol) of Compound C was dissolved in 5 mL of dimethyl sulfoxide (DMSO), and 24 mg (0.60 mmol) of sodium hydride (NaH) was added thereto. The mixed solution was stirred at room temperature. 0.05 mL (0.66 mmol) of ethyl bromide (EtBr) was further added thereto and the resulting mixture was stirred at room temperature. The reaction solution was extracted with chloroform. The extracted material was purified by column chromatography, thereby obtaining 80 mg of Compound D.

In a reaction container, 75 mg of Compound D was dissolved in 5 mL of hydrochloric acid solution. 1 mL (0.5 moles per liter (mol/L)) of a sodium nitrite (NaNO₂) solution (0.5 mol/L, 1 mL) was added dropwise to the mixed solution at a temperature of 5° C. or less. After 1 hour, 100 mg (0.60 mmol) of potassium iodide (KI) was added to the reaction solution for a reaction, thereby obtaining 100 mg of Compound E.

85 mg of Compound E, 112 mg (0.26 mmol) of diphenyl triazine derivative (Compound B), 28 mg (24 μmol) of tetrakis(triphenylphosphine)palladium (Pd(PPh₃)₄), and 0.40 mL (40 mass %, 1.0 mmol) of potassium tetraethyl ammonium (Et₄NOH) were added to 3 mL of toluene. The mixed solution was heated and stirred at a temperature of 100° C., thereby obtaining 90 mg of Compound 1. Compound 1 was extracted with chloroform, purified by using column chromatography, and subjected to structural analysis using nuclear magnetic resonance spectrum (NMR).

Compound B

NMR (300 MHz, CDCl₃): δ 1.42 (12H, s), 7.61 (7H, m), 8.06 (1H, m), 8.80 (4H, m), 8.87 (1H, m), 9.14 (1H, m).

Compound C

NMR (300 MHz, CDCl₃): δ 1.48 (3H, t, J=7.2 Hz), 3.68 (2H, br, s), 4.74 (2H, q, J=7.2 Hz), 6.83 (1H, m), 7.12 (1H, m), 7.23 (1H, m), 7.43 (2H, m), 7.63 (1H, m), 8.04 (1H, m).

Compound D

NMR (300 MHz, CDCl₃): δ 1.48 (3H, t, J=7.2 Hz), 3.78 (2H, br, s), 4.62 (2H, q, J=7.2 Hz), 6.80 (1H, m), 7.05 (1H, m), 7.20 (1H, m), 7.42 (2H, m), 7.62 (1H, m), 8.04 (1H, m).

Compound E

NMR (300 MHz, CDCl₃): δ 1.45 (3H, t, J=7.2 Hz), 4.83 (2H, q, J=7.2 Hz), 6.92 (1H, m), 7.29 (1H, m), 7.53 (2H, m), 7.68 (1H, m), 7.92 (1H, m), 8.07 (1H, m).

Compound 1

NMR (300 MHz, CDCl₃): δ 0.96 (3H, t, J=7.2 Hz), 3.89 (2H, q, J=7.2 Hz), 6.92 (1H, m), 7.20-7.32 (3H, m), 7.28-7.52 (7H, m), 7.68-7.71 (2H, m), 8.11 (2H, m), 8.68 (4H, m), 8.84 (2H, m); LC-MS: m/z 502 (M⁺).

Synthesis Example 2 Synthesis of Compound 19

1) Synthesis of Compound H

In a 50 mL Schlenk tube, 221 mg (0.67 mmol) of Compound G and 13.65 mL of DMSO were added, and air in the tube was replaced by argon gas. 68.5 mg (1.04 mmol) of KOH was added to the Schlenk tube, and the mixed solution was heated and stirred at a temperature of 60° C. in an oil bath. After 2 hours of the heating and stirring the Schlenk tube, the reaction solution was cooled to room temperature. 0.25 mL (3.36 mmol) of ethyl bromide (EtBr) was added to the Schlenk tube. The mixed solution was stirred again for 2 hours at room temperature, and kept overnight.

45 mL of water was added to the reaction solution. An organic layer was extracted twice therefrom with 150 mL of chloroform. The organic layer obtained thereby was collected, washed out with 200 mL of NaCl, and dried with magnesium sulfate. The concentrate obtained by filtering the dry matter was purified by silica gel column chromatography (using hexane-ethyl acetate as a development solvent), thereby obtaining 156 mg (0.39 mmol, yield: 66%) of Compound H.

2) Synthesis of Compound 19

In a 100 mL 3-necked flask, 144 mg (0.36 mmol) of Compound H, 24 mL of 1,4-dioxane, 28.9 mg (0.035 mmol) of Pd(dppf)₂Cl₂CH₂Cl₂, 135 mg (0.531 mmol) of (Bpin)₂(bis(pinacolate)diboron, and 74.8 mg (0.762 mmol) of potassium acetate (KOAc) were added. The air in the flask was replaced by argon gas, and the mixed solution was heated and stirred at a temperature of 100° C. for 7 hours. After the completion of the reaction, the reaction solution was cooled to room temperature, and diluted by 30 ml of chloroform. The diluted mixture was washed out with 20 mL of water and 50 mL of saturated sodium chloride aqueous solution. An organic layer was collected therefrom, dried with magnesium sulfate, filtered, and concentrated. The concentrate was purified by silica gel column chromatography (using hexane-ethyl acetate as a development solvent), thereby obtaining 164.8 mg of Compound I.

In a 100 mL 3-necked flask, 164.8 mg (0.36 mmol) of Compound I, 165 mg (0.616 mmol) of Compound J, 50 mg (0.43 mmol) of Pd(PPh₃)₄, 38.5 mL of tetrahydrofuran (THF), and 16.4 mL of 0.34 molar (M) potassium carbonate solution (K₂CO₃) were added, and the mixture was heat-refluxed for 3 hours. The reaction solution was cooled in an ethanol-ice bath (at a temperature of −10° C.), and filtered to separate powder from the precipitate. The powder obtained therefrom was passed through a silica gel column (using chloroform as a development solvent). The filtered solution was concentrated. The solid obtained therefrom was recrystallized from a toluene-ethanol solvent mixture. The obtained concentrate was subjected to filtration to obtain 126 mg (0.228 mmol, yield: 55%) of Compound 19. The compound obtained therefrom was identified by NMR.

Compound H

NMR (300 MHz, CDCl₃): δ 1.56 (3H, t, J=6.9 Hz), 5.39 (2H, q, J=6.9 Hz), 7.33 (2H, m), 7.45 (2H, m), 7.58 (2H, m), 7.69 (3H, m), 8.19 (2H, m), 8.88 (1H, m).

Compound 19

NMR (300 MHz, CDCl3): δ 1.52 (3H, t, J=7.2 Hz), 5.42 (2H, q, J=7.2 Hz), 7.33 (1H, m), 7.47 (1H, m), 7.52-7.72 (9H, m), 7.82 (2H, m), 8.20 (2H, m), 8.83 (4H, m), 8.97 (2H, m), 9.03 (1H, m); LC-MS: m/z 553 (M+).

Evaluation of Physical Property

Highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of Compound 1 of Synthesis Example 1 and Compound 19 of Synthesis Example 2 were simulated in structural optim/zation using Gausian 09 software (Gausian company) with basis function B3LYP/6-31G*. In addition, the triplet energy levels (i.e., energy levels T1 in a triplet state) of Compound 1 and Compound 19 were calculated based on time-dependent density functional theory (TD-DFT) further using basis function B3LYP/6-31G**.

In addition, in the same manner as described above, HOMO, LUMO, and T1 of a carbazole compound (Comparative Example Compounds 1, 2, and 3 below) and 4,4′-N,N′-dicarbazole biphenyl (CBP) in which charge-transporting groups were substituted in at least one of N-, 2-, and 3-positions in carbazolyl group were simulated. Here, Comparative Compound 1 included a charge-transporting group introduced to the N-position, Comparative Compound 2 included a charge-transporting group introduced to the 2-position, and Comparative Compound 3 included a charge-transporting group introduced to the 3-position.

The material property examination results (HOMO, LUMO, T1) of Compound 1 and Comparative Compounds 1 to 3 are shown in Table 1 below. Here, T1 represents energy levels in a triplet state, and all energy levels were shown with respect to a vacuum level.

TABLE 1 Compar- Compar- Compar- ative ative ative Com- Com- Com- Com- pound pound pound pound 1 1 2 3 CBP HOMO [eV] −5.59 −5.66 −5.66 −5.55 −6.3 LUMO [eV] −2.24 −2.35 −2.17 −2.11 −3 T₁ [eV]  2.88  2.72  2.81  2.79 2.56

Referring to Table 1, Compound 1 was found to have HOMO and LUMO energy levels in a similar range as compared with those of Comparative Compounds 1 to 3 and CBP. This indicates that Compound 1 is suitable as a host material of the organic light-emitting device. In addition, Compound 1 had a greater triplet energy level T₁ than Comparative Compounds 1 to 3 and CBP. Thus, it is appreciated that the carbazole compound according to exemplary embodiments has a larger energy band gap in a triplet state than carbazole compounds to which a charge-transporting group was introduced in at least one of N-, 2-, and 3-positions. Therefore, Compound 1 may be used as a host for green light emission.

The material property examination results of Compound 19 and Comparative Compound 4 used as a red dopant are shown in Table 2 below.

TABLE 2 HOMO [eV] LUMO [eV] T1 [eV] Egg [eV] Compound 19 −5.82 −3.12 2.23 2.70 Comparative −6.11 −3.38 2.03 2.73 Compound 4

Referring to Table 2, it was confirmed that Compound 19 had capability of good charge transport based on HOMO and LUMO energy levels. In addition, Compound 19 had a triplet energy level T1 that is greater than that of Compound 4 served as a red dopant, and that is, Compound 19 was found to be suitable as a red light emission host.

Accordingly, as described above, the carbazole compound according to exemplary embodiments had capability of charge transport by a substituent introduced to the 1-position of a carbazolyl group (or pyrido-carbazolyl group), resulting in a greater energy band gap in a triplet state.

Therefore, the organic light-emitting device including the carbazole compound of exemplary embodiments controls the balance of the charge carriers and enhances emission efficiency and lifespan.

As described above, according to the one or more of the above exemplary embodiments, a carbazole compound is well capable of transporting a charge and has a large energy gap in a triplet state. In this regard, an organic light-emitting device employing the carbazole compound may have low driving voltage, high efficiency, high luminance, and long lifespan characteristics.

It should be understood that the exemplary embodiments described therein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each exemplary embodiment should typically be considered as available for other similar features or aspects in other exemplary embodiments.

While one or more exemplary embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims. 

What is claimed is:
 1. A carbazole compound represented by Formulae 1A or 1B:

wherein in Formulae 1A and 1B, A is -(L₁)_(a1)-(E₁)_(b1), L₁ is selected from a substituted or unsubstituted C₆-C₆₀ arylene group, and a substituted or unsubstituted C₁-C₆₀ heteroarylene group; E₁ is a substituted or unsubstituted electron transporting-cyclic group or a substituted or unsubstituted carbazolyl group, each of which includes at least one N as a ring-forming atom; a1 is selected from integers of 0 to 5; b1 is 1 or 2, provided that when b1 is 2, two groups E₁ are identical to or different from each other; R₁ is selected from a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C₁-C₂₀ alkyl group, a substituted or unsubstituted C₂-C₂₀ alkenyl group, a substituted or unsubstituted C₂-C₂₀ alkynyl group, and a substituted or unsubstituted C₁-C₂₀ alkoxy group; R₂ to R₄ are each independently selected from a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C₁-C₂₀ alkyl group, a substituted or unsubstituted C₂-C₂₀ alkenyl group, a substituted or unsubstituted C₂-C₂₀ alkynyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₁-C₂₀ alkoxy group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), and —B(Q₁₆)(Q₁₇); c1 to c3 are each independently 1 or 2; at least one of substituents of the substituted C₆-C₆₀ arylene group, the substituted C₁-C₆₀ heteroarylene group, the substituted electron transporting-cyclic group, the substituted carbazolyl group, the substituted C₁-C₂₀ alkyl group, the substituted C₂-C₂₀ alkenyl group, the substituted C₂-C₂₀ alkynyl group, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group, the substituted C₁-C₆₀ heteroaryl group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group are selected from a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, and C₁-C₂₀ alkoxy group; a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, and a C₁-C₂₀ alkoxy group, each substituted with at least one of a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), and —B(Q₂₆)(Q₂₇); a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one of a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, and a C₁-C₂₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), and —B(Q₃₆)(Q₃₇); and —N(Q₄₁)(Q₄₂), —Si(Q₄₃)(Q₄₄)(Q₄₅) and —B(Q₄₆)(Q₄₇), wherein Q₁₁ to Q₁₇, Q₂₁ to Q₂₇, Q₃₁ to Q₃₇, and Q₄₁ to Q₄₇ are each independently selected from a hydrogen, a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, a C₁-C₂₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group.
 2. The carbazole compound of claim 1, wherein L₁ is selected from a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-fluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthrenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pyrrolylene group, an imidazolylene group, a pyrazolylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, an isoindolylene group, an indolylene group, an indazolylene group, a purinylene group, a quinolinylene group, an isoquinolinylene group, a benzoquinolinylene group, a phthalazinylene group, a naphthyridinylene group, a quinoxalinylene group, a quinazolinylene group, a cinnolinylene group, a carbazolylene group, a phenanthridinylene group, an acridinylene group, a phenanthrolinylene group, a phenazinylene group, a benzooxazolylene group, a benzoimidazolylene group, a furanylene group, a benzofuranylene group, a thiophenylene group, a benzothiophenylene group, a thiazolylene group, an isothiazolylene group, a benzothiazolylene group, an isoxazolylene group, an oxazolylene group, a triazolylene group, a tetrazolylene group, an oxadiazolylene group, a triazinylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, an imidazopyrimidinylene group, and an imidazopyridinylene group; and a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-fluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthrenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pyrrolylene group, an imidazolylene group, a pyrazolylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, an isoindolylene group, an indolylene group, an indazolylene group, a purinylene group, a quinolinylene group, an isoquinolinylene group, a benzoquinolinylene group, a phthalazinylene group, a naphthyridinylene group, a quinoxalinylene group, a quinazolinylene group, a cinnolinylene group, a carbazolylene group, a phenanthridinylene group, an acridinylene group, a phenanthrolinylene group, a phenazinylene group, a benzooxazolylene group, a benzoimidazolylene group, a furanylene group, a benzofuranylene group, a thiophenylene group, a benzothiophenylene group, a thiazolylene group, an isothiazolylene group, a benzothiazolylene group, an isoxazolylene group, an oxazolylene group, a triazolylene group, a tetrazolylene group, an oxadiazolylene group, a triazinylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, an imidazopyrimidinylene group, and an imidazopyridinylene group, each substituted with at least one of a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a C₆-C₂₀ aryl group, and a C₁-C₆₀ heteroaryl group.
 3. The carbazole compound of claim 1, wherein L₁ is selected from a phenylene group, a naphthylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a pyrrolylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, an isoindolylene group, an indolylene group, a furanylene group, a benzofuranylene group, a thiophenylene group, a benzothiophenylene group, and a triazinylene group; and a phenylene group, a naphthylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a pyrrolylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, an isoindolylene group, an indolylene group, a furanylene group, a benzofuranylene group, a thiophenylene group, a benzothiophenylene group, and a triazinylene group, each substituted with at least one of a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a phthalazinyl group, a quinoxalinyl group, a cinnolinyl group, and a quinazolinyl group.
 4. The carbazole compound of claim 1, wherein a1 is 1 or
 2. 5. The carbazole compound of claim 1, wherein (L₁)_(a1) is represented by one of Formulae 2A to 2F:

wherein in Formulae 2A to 2F, Z₁₁ and Z₁₂ are each independently selected from a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a phthalazinyl group, a quinoxalinyl group, a cinnolinyl group, and a quinazolinyl group; p1 and p2 are each independently an integer of 0 to 4; p3 is an integer of 0 to 3; and * and *′ are each independently indicate a binding site to a neighboring group or atom, wherein *′ indicates a binding site to E₁.
 6. The carbazole compound of claim 1, wherein (L₁)_(a1) is represented by one of Formulae 3A to 3G:

wherein in Formulae 3A to 3G, * and *′ are each independently indicate a binding site to a neighboring group or atom, wherein *′ indicates a binding site to E₁.
 7. The carbazole compound of claim 1, wherein E₁ is selected from a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, a thiazolyl group, an isothiazolyl group, a benzothiazolyl group, an isoxazolyl group, an oxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a carbazolyl group, an imidazopyrimidinyl group, and an imidazopyridinyl group; and a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, a thiazolyl group, an isothiazolyl group, a benzothiazolyl group, an isoxazolyl group, an oxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a carbazolyl group, an imidazopyrimidinyl group, and an imidazopyridinyl group, each substituted with at least one Ar₁, wherein Ar₁ is selected from a phenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthrenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoxazolyl group, a benzoimidazolyl group, a furanyl group, a benzofuranyl group, a thiophenyl group, a benzothiophenyl group, a thiazolyl group, an isothiazolyl group, a benzothiazolyl group, an isoxazolyl group, an oxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyrimidinyl group, and an imidazopyridinyl group; and a phenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthrenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoxazolyl group, a benzoimidazolyl group, a furanyl group, a benzofuranyl group, a thiophenyl group, a benzothiophenyl group, a thiazolyl group, an isothiazolyl group, a benzothiazolyl group, an isoxazolyl group, an oxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyrimidinyl group, and an imidazopyridinyl group, each substituted with at least one of a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof and a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a phthalazinyl group, a quinoxalinyl group, a cinnolinyl group, and a quinazolinyl group.
 8. The carbazole compound of claim 1, wherein E₁ is represented by one of Formulae 4A to 4C:

wherein in Formulae 4A to 4C, Ar₁ is selected from a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a phthalazinyl group, a quinoxalinyl group, a cinnolinyl group, and a quinazolinyl group; Z₂₁ is selected from a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group; a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with at least one of a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a pyridinyl group, a pyrimidinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, and a quinazolinyl group; q1 is an integer of 0 to 3; q2 is an integer of 0 to 2; q3 is an integer of 0 to 4; and * indicates a binding site to a neighboring group or atom.
 9. The carbazole compound of claim 1, wherein E₁ is represented by one of Formulae 5A to 5C:


10. The carbazole compound of claim 1, wherein R₁ is selected from a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group; and a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with at least one of a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a pyridinyl group, a pyrimidinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, and a quinazolinyl group.
 11. The carbazole compound of claim 1, wherein R₁ is selected from a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a pentoxy group.
 12. The carbazole compound of claim 1, wherein R₂ to R₄ are each independently selected from a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, and C₁-C₂₀ alkoxy group; a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, and a C₁-C₂₀ alkoxy group, each substituted with at least one of a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a pyridinyl group, a pyrimidinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, and a quinazolinyl group; a phenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthrenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoxazolyl group, a benzoimidazolyl group, a furanyl group, a benzofuranyl group, a thiophenyl group, a benzothiophenyl group, a thiazolyl group, an isothiazolyl group, a benzothiazolyl group, an isoxazolyl group, an oxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, and an imidazopyridinyl group; a phenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthrenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoxazolyl group, a benzoimidazolyl group, a furanyl group, a benzofuranyl group, a thiophenyl group, a benzothiophenyl group, a thiazolyl group, an isothiazolyl group, a benzothiazolyl group, an isoxazolyl group, an oxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyrimidinyl group, and an imidazopyridinyl group, each substituted with at least one of a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a phthalazinyl group, a quinoxalinyl group, a cinnolinyl group, and a quinazolinyl group; and —N(Q₁₃)(Q₁₄) and —Si(Q₁₅)(Q₁₆)(Q₁₇), wherein Q₁₃ to Q₁₇ are each independently selected from a hydrogen, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a phthalazinyl group, a quinoxalinyl group, a cinnolinyl group, and a quinazolinyl group.
 13. The carbazole compound of claim 1, wherein R₂ to R₄ are each independently selected from a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, and C₁-C₂₀ alkoxy group; a phenyl group, a naphthyl group, a pyridinyl group, and a naphthyridinyl group; a phenyl group, a naphthyl group, a pyridinyl group, and a naphthyridinyl group, each substituted with at least one of a deuterium atom, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a phthalazinyl group, a quinoxalinyl group, a cinnolinyl group, and a quinazolinyl group; and —Si(Q₁₅)(Q₁₆)(Q₁₇), wherein Q₁₅ to Q₁₇ are each independently selected from a hydrogen, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a phthalazinyl group, a quinoxalinyl group, a cinnolinyl group, and a quinazolinyl group.
 14. The carbazole compound of claim 1, wherein R₁ is selected from a methyl group and an ethyl group; and R₂ to R₄ are each independently selected from a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a pentoxy group.
 15. The carbazole compound of claim 1, wherein at least one of R₂ to R₄ is each independently selected from fluorine and a C₁-C₂₀ alkoxy group.
 16. The carbazole compound of claim 1, comprising at least one of Compounds 1 to 30:


17. An organic light-emitting device comprising a first electrode; a second electrode facing the first electrode; and an organic layer disposed between the first electrode and the second electrode, wherein the organic layer comprises an emission layer and at least one carbazole compound of claim
 1. 18. The organic light-emitting device of claim 17, wherein the first electrode is an anode, the second electrode is a cathode, and the organic layer comprises i) a hole transport region formed between the first electrode and the emission layer, wherein the hole transport region comprises at least one of a hole injection layer, a hole transport layer, and an electron blocking layer, and ii) an electron transport region formed between the emission layer and the second electrode, wherein the electron transport region comprises at least one of a hole blocking layer, an electron transport layer, and an electron injection layer.
 19. The organic light-emitting device of claim 17, wherein the emission layer comprises the carbazole compound of claim
 1. 20. The organic light-emitting device of claim 17, wherein the emission layer comprises a phosphorescent dopant. 